Operator (computer programming)

In computer programming, an operator is a programming language construct that provides functionality that may not be possible to define as a user-defined function (e.g. sizeof in C) or has syntax different from that of a function (e.g. infix addition as in a+b ). Like other programming language concepts, operator has a generally accepted, although debatable, meaning among practitioners. Some operators are represented with symbols characters typically not allowed for a function identifier to allow for presentation that is more familiar looking than typical function syntax. For example, a function that tests for greater-than could be named gt , but many languages provide an infix symbolic operator so that code looks more familiar. For example, this: if gt(x, y) then return Can be: if x > y then return Some languages allow a language-defined operator to be overridden with user-defined behavior and some allow for user-defined operator symbols. Operators may also differ semantically from functions. For example, short-circuit Boolean operations evaluate later arguments only if earlier ones are not false.

In computer programming, an operator is a programming language construct that provides functionality that may not be possible to define as a user-defined function (e.g. sizeof in C) or has syntax different from that of a function (e.g. infix addition as in a+b ). Like other programming language concepts, operator has a generally accepted, although debatable, meaning among practitioners. Some operators are represented with symbols characters typically not allowed for a function identifier to allow for presentation that is more familiar looking than typical function syntax. For example, a function that tests for greater-than could be named gt , but many languages provide an infix symbolic operator so that code looks more familiar. For example, this: if gt(x, y) then return Can be: if x > y then return Some languages allow a language-defined operator to be overridden with user-defined behavior and some allow for user-defined operator symbols. Operators may also differ semantically from functions. For example, short-circuit Boolean operations evaluate later arguments only if earlier ones are not false. In general, an operator may be prefix, infix, postfix, matchfix, circumfix or bifix, and the syntax of an expression involving an operator depends on its arity (number of operands), precedence, and (if applicable), associativity. Most programming languages support binary operators and a few unary operators, with a few supporting more operands, such as the ?: operator in C, which is ternary. There are prefix unary operators, such as unary minus -x , and postfix unary operators, such as post-increment x++ ; and binary operations are infix, such as x + y or x = y . Infix operations of higher arity require additional symbols, such as the ternary operator ?: in C, written as a ? b : c – indeed, since this is the only common example, it is often referred to as the ternary operator. Prefix and postfix operations can support any desired arity, however, such as 1 2 3 4 + . The semantics of an operator may significantly differ from that of a normal function. For reference, addition is evaluated like a normal function. For example, x + y can be equivalent to a function add(x, y) in that the arguments are evaluated and then the functional behavior is applied. However, assignment is different. For example, given a = b the target a is not evaluated. Instead its value is replaced with the value of b . The scope resolution and element access operators (as in Foo::Bar and a.b , respectively, in the case of e.g. C++) operate on identifier names; not values. In C, for instance, the array indexing operator can be used for both read access as well as assignment. In the following example, the increment operator reads the element value of an array and then assigns the element value. ++a[i]; The C++ << operator allows for fluent syntax by supporting a sequence of operators that affect a single argument. For example: cout Compound assignment (aka augmented assignment) in C/C++: += , -= , *= , /= , %= , , >>= , &= , ^= , |= Fused: such as

Text derived from https://en.wikipedia.org/w/index.php?oldid=1378515151 under CC BY-SA 4.0; modifications have been made.